Why do we call phoney Doctors 'Quacks'? Where does the term originate from?

Answer 1

The word "quack" may derive from "quacksalver," an archaic word originally of Dutch origin (spelled kwakzalver in contemporary Dutch), meaning "boaster who applies a salve." There is also a strong resemblence to the German word "quacksalber" which means "questionable salesperson (literal translation: quack salver)." In the Middle Ages the word quack itself meant "shouting. The quacksalvers sold their wares on the market shouting in a loud voice."

Answer 2

It’s an abbreviation of an old Dutch word that in the modern language is spelled kwakzalver. It comes from quack, an early modern Dutch word meaning a person who chatters or prattles (probably connected to the English word for the noise a duck makes), and salf, essentially the same word as our salve. So a quacksalver was somebody who boasted about the virtues of his remedies, so it later became attached to a person who claimed to have miraculous medications. The longer form was common in the sixteenth century, but it was abbreviated later. The similarity of the full-length word to quicksilver, or mercury, and the once common use of that element in medicine (especially to treat diseases such as syphilis), falsely suggests a link with the name. But there’s no connection.